body {
    width: 100%;
    max-width: 640px;
    min-width: 320px;
    margin: 0 auto;
    font-family: -apple-system, Helvetica, sans-serif;
    line-height: 1.5;
    font-size:14px;
    color:#666;
    height: 2000px;
}
img {
    vertical-align: middle;
}
a {
    color:#666;
    text-decoration: none;
}
ul {
    margin:0;
    padding:0;
    list-style:none;
}
div {
    box-sizing: border-box;
}
/* 顶部 */
.app {
    height: 45px;
}
.app ul li {
    float:left;
    height:45px;
    background-color: #333;
    line-height:45px;
    text-align:center;
    color:#fff;
}
.app ul li:nth-child(1) {
    width: 8%;
}
.app ul li:nth-child(1) img{
    width:10px;
}
.app ul li:nth-child(2) {
    width: 10%;
}
.app ul li:nth-child(2) img {
    width: 30px;
    vertical-align: middle;
}
.app ul li:nth-child(3) {
    width: 57%;
}
.app ul li:nth-child(4) {
    width: 25%;
    background-color: #f63515;
}
/* 搜索 */
.search-wrap {
    position:fixed;
    width: 100%;
    height: 44px;
    min-width: 320px;
    max-width: 640px;
}
.search-btn {
    position:absolute;
    top:0;
    left:0;
    width: 40px;
    height: 44px;
}
.search-btn::before {
    content:'';
    display:block;
    width:20px;
    height: 18px;
    background: url(../images/s-btn.png) no-repeat;
    background-size: 20px 18px;
    margin:14px 0 0 15px  ;
}
.search-login {
    position:absolute;
    top:0;
    right:0;
    width: 40px;
    height: 44px;
    color:#fff;
    line-height: 44px;
}
.search {
    position:relative;
    height: 30px;
    background-color: #fff;
    margin:7px 50px;
    border-radius: 15px;
}
.jd-icon {
    width: 20px;
    height: 15px;
    position:absolute;
    top:8px;
    left:13px;  
    background:url(../images/jd.png) no-repeat ;
    background-size:20px 15px;
}
.jd-icon::after {
    content:'';
    position:absolute;
    top:0;
    right:-8px;
    width: 1px;
    height: 15px;
    background-color: #ccc;
}
.jd-s{
    width: 18px;
    height: 15px;
    background: url(../images/jd-sprites.png) no-repeat -80px 0px;
    background-size: 200px auto;
    position: absolute;
    top:8px;
    left:45px   ;
} 
.slider img {
    width: 100%;
}
.brand {
    border-radius: 20px 20px 0 0;
    overflow: hidden;
}
.brand div {
    float: left;
    width: 33.33%;
}
.brand div img {
    width: 100%;
}
/* nav部分 */
nav {
    padding:5px 0;
}
nav a {
    float:left;
    width: 20%;
    text-align: center;
}
nav a img {
    width: 40px;
    margin:10px 0;
}
nav a span{
    display: block;
}
.news {
    margin-top: 10px;
}
.news a {
    float: left;
    box-sizing: border-box;
}
.news a img {
    width: 100%;
}
.news a:nth-child(1) {
    width: 50%;
}
.news a:nth-child(n+2) {
    width: 25%;
    border-left: 1px solid #ccc
}